The present disclosure relates to additives that can be used to crosslink polymers, such as polycarbonate polymers, for improved properties. Also included are compositions containing such additives, as well as articles (e.g. sheets, films, molded components, etc.) formed from such compositions. More specifically, the additive comprises a photoactive group derived from a monofunctional benzophenone. Polymeric blends of the additive with polycarbonate-polysiloxane resins are disclosed. Upon exposure to ultraviolet radiation, crosslinking will occur between the photoactive additive and the polymer resin, improving overall chemical resistance, flame retardance, and other characteristics.
Polycarbonates (PC) are synthetic engineering thermoplastic resins, and are a useful class of polymers having many beneficial properties. They are useful for forming a wide variety of products, such as by molding, extrusion, and thermoforming processes. Polycarbonate resins are both strong and transparent, and are used for a number of different commercial applications, including electronic engineering (E&E) parts, mechanical parts, etc. Because of their broad use, particularly in electronic applications and auto part applications, the desired properties of polycarbonates include high impact strength and toughness, heat resistance, weather and ozone resistance, and good ductility.
Polycarbonate polymers/resins and blends containing polycarbonate polymers exhibit flame retardance properties. However, such polymers drip when exposed to a flame, and this behavior worsens as the wall thickness decreases. This behavior greatly diminishes their use in transparent and opaque thin wall applications where a V0 or 5VA flame retardance rating is required. These polymers also have relatively poor chemical resistance. It would be desirable to provide additives that can improve these properties.